The present invention relates generally to an apparatus and method for the closure of wounds in body tissue, and more particularly to an apparatus and method for the suture of puncture sites in body lumens accessible through a tissue tract.
Transluminal medical procedures have seen a marked rise in popularity during the past decade due to the much reduced surgical damage to healthy tissue, recovery time, and ultimate cost to the patient associated with these procedures. Such procedures typically require an incision formed in a body lumen and the overlying tissue through which catheters, guide wires, laparoscopes, endoscopes, and similar medical devices can be inserted into the patient's vascular system. The incisions are created with instruments such as trocars, and may measure from 5 to upwards of 15 mm in diameter. After the intravascular procedure is complete, the incision must be closed and sealed as quickly as possible to prevent further bleeding.
Unfortunately, the size of the incision is usually large enough to permit profuse bleeding, but too small for the convenient application of conventional wound closure techniques such as suturing. Other methods have been proposed, including the use of collagen and other types of plugs placed outside the lumen and near the wound. Some plugs are designed to be placed directly within the lumen and secured against the inner wall of the lumen by an external suture attached to the plug. In yet other similar closure methods, a clotting agent such as a foam, gel, or powder is dispensed within the wound. These methods all tend to cause the at least partial deposition of a plug or clotting agent within the lumen, whether by design or unintentionally, and thus result in the partial occlusion of the flow of blood through the lumen near the site of the wound. This is an unfortunate side effect that can lead to complications such as thrombosis and is therefore undesirable.
Another common closure technique employs continuous pressure applied to the wound site to allow the patient's blood to clot sufficiently to seal the wound. This technique, however, is usually very time consuming for both patient and medical personnel, thus partially negating one of the main advantages of transluminal procedures. In addition, a hematoma may occur if the patient moves while the pressure is being applied and therefore additional rest and observation in the hospital is required, further driving up the cost and time associated with the procedure.
Sutures remain the preferred method of sealing wounds, but the small size of the typical wound formed during a transluminal procedure renders the application of sutures a delicate and difficult task. Traditionally the surgeon would introduce a suture needle through the tissue tract and into the body lumen, manipulate the needle with a grasping instrument into position, then urge it to penetrate and pass through the lumen wall near the wound site and pull the suture material therethrough. This procedure involves difficult manipulations and maneuvers in a small space and through a small opening, and is therefore time consuming and burdensome.
Due to the ever increasing number of transluminal procedures performed each year, a great deal of effort has been devoted to the development of quicker, safer methods for post-operative suturing of endoscopic wounds. Practically all viable methods involve the use of a specially developed device for placing sutures in the lumen and through the body tissue. Some devices employ needles to carry opposite ends of a suture through the tissue surrounding the wound, and then means for retrieving the ends of the suture from within the body lumen and out through the wound. Such means may include an expandable mesh (U.S. Pat. No. 5,496,332 to Sierra et al.), a flexible membrane capturing anchors attached to the ends of the suture (U.S. Pat. No. 5,391,182 to Chin), and an expandable bow assembly (U.S. Pat. Nos. 5,304,184 and 5,476,469 to Hathaway et al.). A drawback to the method employed by these devices is that the suture ends pass from within the lumen and out through the wound opening, and are thereby trapped between the tissue walls surrounding the wound when the suture is tensioned to close the opening. This suture configuration prevents the tissue walls from fully contacting each other and thus may require an extended period of time to heal. In addition, this configuration also requires that the suture knot tied by the surgeon must lie within the lumen, and therefore in most cases the surgeon cannot tie a sufficiently tight knot to prevent any further bleeding and to ensure minimal scarring of the tissue upon healing. Finally, most such devices require the surgeon to blindly capture the ends of the suture within the lumen while blood courses through the lumen with the patient's heart beat, making exact placement and capture of the suture ends difficult and imprecise.
Other suturing devices employ tubes carrying needles mounted on extendible platforms that advance out of the distal end of the tube once the distal end has been positioned within the lumen. The needles may be straight or curved, and carry sutures so that when the device is retracted from the lumen the needles pierce the side walls of the wound and thereby carry the sutures through the surrounding tissue. Devices of this type are disclosed in, e.g., U.S. Pat. No. 5,374,275 to Bradley et al., U.S. Pat. No. 5,364,408 to Gordon, U.S. Pat. No. 5,320,632 to Heidmueller, U.S. Pat. No. 5,403,329 to Hinchcliffe, U.S. Pat. No. 5,368,601 to Sauer et al., and international publications WO 94/13211 and WO 95/13021. A relatively similar device is disclosed in U.S. Pat. No. 5,431,666 to Sauer et al., wherein the device has a distal end with a suture equipped with ferules at either end placed therein. The distal end is positioned within the lumen and beneath the side walls of the wound, and sharp needles are driven through the side wall tissue to engage the ferules and pull the suture out. These devices are preferable because they create a cleaner, tighter seal of the wound, and are somewhat easier to operate because the suture ends do not have to be captured blindly within the lumen. Unfortunately, however, such devices are relatively complex and employ a significant number of moving parts. These devices are therefore relatively costly to manufacture and are also more prone to mechanical failure. In addition, such devices cannot be easily manufactured with very small diameters because of the complex mechanisms that must fit entirely within the device, especially when the needles are curved, and thus some of the devices may not be suited to suturing small diameter wounds.
The need continues to exist for a suturing method that will cleanly and tightly suture small as well as larger diameter wounds with an uncomplicated, dependable, inexpensive apparatus that is fail proof and simple to use. The present invention meets these needs.